Depression is a common mental disease, mainly manifested as feeling down, reduced interest, pessimism, slow thinking, lack of initiative, self-accusation and self-guilty, poor diet and sleep, fear of suffering from various diseases, feeling unwell in many parts of the body, and suicidal thoughts and behaviors in serious cases. In the fourth edition of “Diagnostic and Statistical Manual of Mental Disorders” published by the American Psychiatric Association, the depression is classified into three types: a severe depression, a dysthymia disorder and other unspecified depressions.
Factors causing depressions include: genetic factors, physical factors, central nervous medium functions and metabolic abnormalities, mental factors, etc. In efforts to treat the depressions, various antidepressant compositions have been developed, such as sertraline, flosi, paroxetine, fluvoxamine, and bupropion. Although these drugs are effective, they often produce problematic side effects, such as narcolepsy, confusion, inability to concentrate and sexual dysfunction. Moreover, these drugs have the problem of long onset time, which requires about 6 to 8 weeks to show any desired therapeutic effect.